A Cochrane review «»1 «Yousefi-Nooraie R, Schonstein E, Heidari K, Rashid...»1 included 7 studies with a total of 384 subjects. Three small studies (168 people) separately showed statistically significant but clinically unimportant pain relief for LLLT versus sham therapy for sub-acute and chronic low-back pain at short-term and intermediate-term follow-up (up to six months). One study (56 people) showed that LLLT was more effective than sham at reducing disability in the short term. Three studies (102 people) reported that LLLT plus exercise were not better than exercise, with or without sham in the short-term in reducing pain or disability. Two studies (90 people) reported that LLLT was not more effective than exercise, with or without sham in reducing pain or disability in the short term.
Comment: The quality of evidence is downgraded by inconsistency (heterogeneity in interventions and outcomes), imprecise results (few patients and wide confidence intervals) and study quality (several issues).